This invention relates to an improved catalytic reforming process. In another aspect, this invention relates to a method for inhibiting the deactivation of a reformer catalyst.
Catalytic reforming is a well established refining process employed by the petroleum industry for upgrading low-octane hydrocarbons to higher-octane hydrocarbons. Typically, catalytic reforming involves the contacting of a naphtha hydrocarbon feed with a reformer catalyst under elevated temperatures and pressures.
Reformer catalysts typically comprise a metal hydrogen transfer component or components, a halogen component, and a porous inorganic oxide support. A reformer catalyst which has been employed widely throughout the petroleum industry comprises platinum as the metal hydrogen transfer component, chlorine as the halogen component, and alumina as the support.
Also, additional metallic promoter components, such as rhenium, iridium, ruthenium, tin, palladium, germanium and the like, have been added to the basic platinum-chlorine-alumina catalyst to create a bimetallic catalyst with improved activity, selectivity, or both.
In a conventional reforming process, a series of two to five reformer reactors constitute the heart of the reforming unit. Each reformer reactor is generally provided with a fixed bed or beds of catalyst which receive upflow or downflow feed. Each reactor is provided with a heater because the reactions which take place therein are predominantly endothermic. In a typical commercial reformer, a naphtha feed with a diluent of hydrogen or hydrogen recycled gas is passed through a preheat furnace, then downward through a reformer reactor, and then in sequence through subsequent interstage heaters and reactors connected in series. The product of the last reactor is separated into a liquid fraction and vaporous effluent. The vaporous effluent, a gas rich in hydrogen, may then be used as hydrogen recycled gas in the reforming process.
During operation of a conventional catalytic reforming unit, the activity of the reformer catalyst gradually declines over time. There are believed to be several causes of reformer catalyst deactivation, including, (1) formation of coke within the pores, as well as on the surface, of the catalyst, (2) agglomeration of the catalyst metal component or components, and (3) loss of the halogen component. Deactivation of a reformer catalyst can have the following negative impacts on the reforming process: (1) lower product octane 5 number; (2) higher required reaction temperature; (3) higher required reaction pressure; (4) decreased time between required catalyst regeneration (cycle time); (5) increased requirement for hydrogen; and (6) decreased selectivity.
It is known that processing a reformer feed which contains high concentrations of water can accelerate deactivation of a reformer catalyst by, for example, stripping the halogen component and increasing the rate of coke formation on the catalyst. To counteract the negative effects of processing a xe2x80x9cwetxe2x80x9d reformer feed, the reformer feed can be pre-dried; however, drying a wet reformer feed is an expensive process.
It has recently been discovered that adding small quantities of an inorganic aluminum chloride compound to a reformer feed during reforming can inhibit deactivation of the reformer catalyst. However, due to their solubility properties, inorganic aluminum chloride compounds are difficult to inject into the reformer feed in uniform quantities.
It is an object of the present invention to provide an improved reforming process employing a novel method which inhibits deactivation of a reformer catalyst.
It is a further object of the present invention to provide a method for inhibiting the deactivation of a reformer catalyst while reforming a wet hydrocarbon feed.
A still further object of the present invention is to provide a method for causing the presence of an inorganic aluminum chloride compound in a reformer reaction zone that overcomes the problems associated with injecting inorganic aluminum chloride compounds into a reformer feed.
Further objects and advantages of the present invention will become apparent from consideration of the specification and appended claims.
Accordingly, one embodiment of the invention is a process comprising charging a reformer feed having a concentration of an organic aluminum halide compound in the range of from about 0.001 to about 500 parts per billion by weight (ppbw) to a reformer reactor operating under reforming conditions and containing a reformer catalyst.
Another embodiment of the invention is a reforming process that comprises charging a hydrocarbon feed to a reformer reactor operated under reforming conditions and introducing in combination an organic aluminum halide compound into the hydrocarbon feed both in an amount that is effective to inhibit deactivation of the reformer catalyst.
Another embodiment of the invention is a reforming process that comprises charging a hydrocarbon feed to a reformer reactor operated under reforming conditions and introducing an organic aluminum halide compound and a nonmetallic chloride compound into the hydrocarbon feed both in amounts that are effective to inhibit deactivation of the reformer catalyst.